Members of the Stephanie Roper Committee came to the Maryland General Assembly today carrying 24 boxes crammed with petitions signed by 92,648 people saying that criminal sentencing laws should be tightened. They packed the joint legislative committee hearing room, hot with TV lights, and filled it with tales of horror and cries for justice.

For more than four hours, supporters of the committee, named for the 22-year-old Frostburg State College student who was raped and murdered last year, marched to the witness table and urged members of the House Judiciary Committee and the Senate Judicial Proceedings Committee to pass laws that would make it more difficult for criminals to go free. The committee was formed after the two men convicted of raping, shooting and burning Stephanie Roper were given prison terms that would make them eligible for parole in 12 years.

Under consideration today were bills that would tighten parole procedures; make it more difficult for a defendant to plead mitigating circumstances; allow relatives of crime victims to testify at sentencing on the impact of the crime on them, and most significantly, give juries the option to order life terms without parole to persons convicted of first-degree murder. Maryland juries now can give a defendant either the death penalty or a life sentence that includes possible parole.

The Roper committee spokesmen emphasized that revenge was not their motive. They said the death penalty is just one way of keeping criminals off the streets and that to them life terms without parole would serve the same purpose.

The most dramatic testimony came from Roberta Roper, mother of Stephanie Roper. Her eyes glistening but her voice clear and strong, she spoke--without a prepared text--about being a victim.

"We have suffered our nuclear holocaust," Roper said. "We have been victimized twice, first by the acts against our daughter and then by a judicial system that made a travesty of justice . . . We are committed to being the voice of victims. Our motive is justice . . .

"We victims are left on our own to attempt to repair what crimes have destroyed. What we cannot repair, we are forced to endure. How do we explain to our children our loss? All we can do is try to change the laws."

When she finished, the audience burst into applause. House Judiciary Committee Chairman Joseph E. Owens (D-Montgomery), who has often threatened to clear hearing rooms because of overzealous reactions, simply waited until the applause subsided.

Later, Vic Pietkewicz, chairman of the Roper committee, presented the legislators with the petitions, piled in boxes behind the witness table. He said 98 percent of the people asked to sign the petition had done so.

In the face of the emotional testimony given by the Roper committee supporters, lawyer Edward Genn, representing the American Civil Liberties Union, said after speaking against the proposals, "All I have received for my work so far is abuse. I had hoped this would not become personal."

Genn also spoke with emotion: "While we are concerned deeply about the victims, let us not make the Constitution a victim." He poked at what he said were legal holes in the language in many of the bills. "Any lawyer with a modicum of experience would look at these bills and say, 'My goodness,' after 15 or 20 minutes."

Many legislators on the House and Senate committees said they agree with Genn. They predicted that one or two of the bills might pass, but said a large portion of the package will die in committee, especially on the House side, where the crusty Owens is always skeptical about major changes in laws.

"You have to be certain that the problem is the law and not the circumstances of a particular case," Owens said recently. "You don't assume a law is bad because of one bad case."

His counterpart, Sen. Thomas V. Mike Miller, is a sponsor of much of the legislation and represents the part of southern Prince George's County where the Roper family lives. Miller is especially pushing bills that would remove voluntary use of alcohol or drugs as mitigating circumstances and for the life term without parole.